Field of the Invention
The present invention concerns a method of bringing to temperature and holding at temperature the interior of a thermally insulated enclosure with no continuous supply of energy, and a device for bringing to temperature and holding at temperature the interior of a thermally insulated enclosure capable of implementing the aforementioned method.
Description of Related Art
Certain compounds in the gaseous state can be reversibly absorbed by another compound in the liquid state. This is true of water in vapor form which can be absorbed by a solution of lithium bromide. There are also solids that are capable of reacting with gases during a reversible exothermic reaction to produce a solid product. This is the case, for example, for alkaline or alkaline-earth metal chlorides that react particularly with ammonia. There are also solid compounds such as zeolites on which a gas can be absorbed reversibly. The aforementioned absorption, adsorption and chemical reaction are exothermic and reversible; they are currently used for the production of cold and heat.
The document WO 2006/100412 A1 describes a device that comprises a thermally insulated enclosure, means of placing in circulation the air contained in the enclosure and a thermochemical system. Said thermochemical system comprises a gas reservoir capable of being placed in communication, through valve means, with a reactor; said reactor contains a solid reagent capable of reacting with the gas contained in the reservoir in order to form, during a reversible exothermic chemical reaction, a solid product. When the valve means are opened, the pressure of the gas in the reservoir decreases continuously because the gas is consumed in the reactor: the drop in pressure in the reservoir causes an absorption of heat from the ambient environment. At the same time, the chemical reaction that takes place in the reactor produces heat. The device described in the aforementioned document, thanks to the means of placing the air in circulation, makes it possible either to heat the air contained in the enclosure in contact with the reactor, or to cool it in contact with the reservoir. Said device therefore makes it possible either to heat or cool the thermally insulated enclosure, without external supply of energy, once the chemical reaction has begun. When all of the gas has reacted with the reagent, the reactor must then be reheated to induce the reverse endothermic reaction and refill the reservoir with gas. During this so-called regeneration phase, the device can no longer be used. The autonomy of the device is therefore directly related to the quantity of reagents, and particularly of the gas contained in the reservoir.
If it is desired to increase the autonomy of the aforementioned device, one solution consists of increasing the quantity of gaseous reagent. The device then becomes very cumbersome and heavy. Moreover, because the reactor is also of a large size, its regeneration phase becomes longer.
Furthermore, the document WO 2013/164539 A1 describes a device comprising two thermochemical systems that function alternately. When one of the thermochemical systems is in the regeneration phase by means of the electrical resistances that surround the reactor, the other is in the cold production phase. Means of determining the progress of the reaction make it possible to optimize the alternating of the regeneration phases. This device is not autonomous because its operation requires that one of the reactors be in the regeneration phase, which means that the device during its operation is always connected to a source of electricity. The only means of making the device mobile and autonomous is to associate a source of electricity with it that is capable of continuously supplying the electricity during its operation. Such a device proves to be expensive and cumbersome.